The invention relates to a collapsible two-wheeled trolley or hand truck.
Such a trolley is known which comprises a vertical frame formed from a pair of longitudinal sections, the lower end of which has two wheel carriers provided with wheels and which are swivelable about generally vertical axes lying in the plane of the vertical frame. The wheel carriers can be swivelled out and secured by securing means. A shovel is provided as a means for supporting loads. The shovel can be swivelled about an additional swivelling axis which runs generally horizontally and perpendicular to the swivelling axes of the wheel carriers. The upper end of the frame is designed as a manual gripping end. The longitudinal sections of the vertical frame are connected together between the mobile frame and the gripping end and by at least one transverse bar, whereby the wheel carrier and shovel are coupled on the lower end of the corresponding longitudinal sections.
In many cases, small loads are to be transported simply and certainly with a simple transportation means that can also be transported with the load, for example goods for purchase from a car at home or in the scope of a recreational activity; for instance, in the preparation of a sailing mast for equipping a boat, many objects for the outfitting must be brought to the boat which cannot be reached by car. In these cases trolleys are suited for transporting materials. It is a necessity to be able to collapse the trolley to as flat and space-saving a condition as possible and to make the trolley as light-weight as possible for a private household as well as for taking such a trolley in the car or on board a boat or similar vehicle.
Light-weight trolleys which can be collapsed are known from U.S. Pat. No. 3,043,603. The trolley proposed there has a rigid vertical frame with a transverse link as a handle. On the lower end of the vertical frame a shovel is attached so that it can be swivelled about an axis lying transverse to the plane of the vertical frame. Wheel carriers necessary to roll the trolley are provided in the area of the lower end, which can be swivelled-in and have securing means which fix the wheel carriers in a swivelled-out position. The projections provided for this wheel-securing function which engage in an opening in the swivel sleeves of the wheel carriers may not, however, enable the required angled position of the wheel carriers to be adequately fixed for secure travelling, especially for long use. In addition, significant forces on the projection producing the securement are to be expected for this kind of fixing, with slight positioning forces affecting the wheels due to the large mechanical advantage, so that deformations in the area of the swivel sleeves hamper the ability to swivel the wheel carriers.
Another type of fixing of the wheel carriers is described in German Document GM-19 43 253; here, the wheel carrier is fixed with a locking pin. The trolley described in this publication has in addition a collapsible shovel blade and foresees the possibility to reduce the size of the vertical frame designed as a gripping frame by folding the frame. The shovel taking on the load is likewise foldably coupled on the vertical frame.
German Document GM-19 82 824 describes a very costly construction, in which the swivelling in of the wheels is combined with the folding of the handle portion of the pushing frame.
Additional trolleys, preferably for transporting travel bags, are described by U.S. Pat. No. 4,335,985 and Swiss Patent 217,650.
Finally, European Published Application No. 0 352 515 relates to a collapsible two-wheeled trolley for transporting small loads for private or recreational use, having a vertical frame built from a pair of longitudinal sections. The lower end of the vertical frame carries a mobile frame with two wheel carriers provided with a wheel and being swivelable about a generally vertical axis running in the plane of the vertical frame and that can be set in a swivelled-out condition by securing means. A shovel provided as a means for accepting loads can be swivelled about an additional swivelling axis which runs generally horizontally and perpendicular to the swivelling axes of the wheel carriers. The upper end of the vertical frame is designed as a gripping end. The longitudinal sections of the vertical frame are pivotably connected together at a location between the wheeled lower end and the gripping end to be divided into upper and lower sections, wherein the upper section can be folded over the lower section. The wheel carrier and shovel are coupled on the lower section. A lock is provided for securing the wheel carriers in the unfolded position. For these trolleys suited for (relatively) small loads, larger loads cause the wheel carriers to slip out of the locked position so that the trolley loses its maneuverability.
The object of the invention is to propose a further development of a trolley of the general type described above such that a safe transport of heavy loads is made ergonomically possible while maintaining the advantages, whereby the trolley can be converted from the rest position to the position of use, so that it takes up as little space as possible in the rest position and whereby the trolley itself can be economically manufactured.